﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

#nullable disable

using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
using System.Reflection;

namespace System.Windows.Forms
{
    /// <summary>
    ///  TreeNodeConverter is a class that can be used to convert
    ///  TreeNode objects from one data type to another.  Access this
    ///  class through the TypeDescriptor.
    /// </summary>
    public class TreeNodeConverter : TypeConverter
    {
        /// <summary>
        ///  Gets a value indicating whether this converter can
        ///  convert an object to the given destination type using the context.
        /// </summary>
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(InstanceDescriptor))
            {
                return true;
            }
            return base.CanConvertTo(context, destinationType);
        }

        /// <summary>
        ///  Converts the given object to another type.  The most common types to convert
        ///  are to and from a string object.  The default implementation will make a call
        ///  to ToString on the object if the object is valid and if the destination
        ///  type is string.  If this cannot convert to the destination type, this will
        ///  throw a NotSupportedException.
        /// </summary>
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType is null)
            {
                throw new ArgumentNullException(nameof(destinationType));
            }

            if (destinationType == typeof(InstanceDescriptor) && value is TreeNode)
            {
                TreeNode node = (TreeNode)value;
                MemberInfo info = null;
                object[] args = null;

                if (node.ImageIndex == -1 || node.SelectedImageIndex == -1)
                {
                    if (node.Nodes.Count == 0)
                    {
                        info = typeof(TreeNode).GetConstructor(new Type[] { typeof(string) });
                        args = new object[] { node.Text };
                    }
                    else
                    {
                        info = typeof(TreeNode).GetConstructor(new Type[] { typeof(string), typeof(TreeNode[]) });

                        TreeNode[] nodesArray = new TreeNode[node.Nodes.Count];
                        node.Nodes.CopyTo(nodesArray, 0);

                        args = new object[] { node.Text, nodesArray };
                    }
                }
                else
                {
                    if (node.Nodes.Count == 0)
                    {
                        info = typeof(TreeNode).GetConstructor(new Type[] {
                            typeof(string),
                            typeof(int),
                            typeof(int)});
                        args = new object[] {
                            node.Text,
                            node.ImageIndex,
                            node.SelectedImageIndex};
                    }
                    else
                    {
                        info = typeof(TreeNode).GetConstructor(new Type[] {
                            typeof(string),
                            typeof(int),
                            typeof(int),
                            typeof(TreeNode[])});

                        TreeNode[] nodesArray = new TreeNode[node.Nodes.Count];
                        node.Nodes.CopyTo(nodesArray, 0);

                        args = new object[] {
                            node.Text,
                            node.ImageIndex,
                            node.SelectedImageIndex,
                            nodesArray};
                    }
                }

                if (info != null)
                {
                    return new InstanceDescriptor(info, args, false);
                }
            }

            return base.ConvertTo(context, culture, value, destinationType);
        }
    }
}
